Gas blast circuit breaker and operating means therefor



Dec. 29, 1964 s. M. GONEK ETAL 3,163,737

GAS BLAST CIRCUIT BREAKER AND OPERATING MEANS THEREFOR Filed March 21, 1961 3 Sheets-Sheet l Dec. 29, 1964 s. M. GONEK ETAL 3,153,737

GAS BLAST CIRCUIT BREAKER AND OPERATING MEANS THEREFOR Filed March 21, 1961 S'Sheets-Sheec 2 F IG. 2

Dec. 29, 1964 M. GONEK ETAL 3,

GAS BLAST CIRCUIT BREAKER AND OPERATING MEANS THEREFOR Filed March 21 1961 3 Sheets-Sheet 3 FIG.4

United States Patent Office GAS BLAST CIRCUIT BREAKER AND OPERATING MEANS THEREFQR Stanislaw lldieczyslaw Gonek and Henry Rowlinson,

tattord, England, and Artur Goldner, Geneva, Switzerland, assignors to The English Electric Company Limited, London, England, a British company Filed Mar. 21, 1961, Ser. No. 97,185 Claims priority, application Great Britain, Mar. 23, 19x30, 10,2?1/69 8 @laiins. (til. 200-148) This invention relates to electric circuit-brealcers.

According to the invention a gas-blast electric circuitbreaker has a main circuit interrupter, a resistor connected electrically in parallel with said main circuit interrupter, a resistor circuit interrupter connected in series with said resistor, a source of gas under pressure connected to said main circuit interrupter, a first pressure-responsive means connected to said main circuit interrupter to operate it, second pressure-responsive means connected to said resistor circuit interrupter to operate it, an exhaust valve operable independently of said interrupters, first passage means connecting said first pressure-responsive means to said exhaust valve, second passage means connecting said second pressure-responsive means to said exhaust valve, whereby opening of said exhaust valve causes operation of both said main circuit interrupter and said resistor circuit interrupter, and further passage means connecting said main circuit interrupter to said exhaust valve, whereby on openins of said main circuit interrupter a blast of said gas under pressure passes over said main interrupter and through said exhaust valve.

An electric circuit-breaker in accordance with the invention will now be described with reference to the accompanying drawings, of which:

FIG. 1 is a schematic diagram showing the electric and pneumatic circuits of the circuit-breaker;

FIG. 2 shows the electric circuit-breaker of FIG. 1 in greater detail; and

FIG. 3 shows a modification of the construction of FIG. 2, and

FIG. 4 is a view corresponding to FIG. 2 with the parts in different positions.

In the electric circuit-breaker shown in FIGS. 1 and 2, the current flows between terminals it; and ii. in parallel with the main circuit interrupter 12 are a resistor and a resistor circuit interrupter TM- in series with the resistor 13; similarly the main circuit interrupter 15 has in pa:-- allel with it the resistor 16 and the resistor circuit interrupter 1'7. The main interrupters i2 and 15 are con: nected in series and the resistor interrupters i i and it? are also connected in series. All four or the interrupters l2, l4, l and T7 are pneumatically operated by one and the same exhaust valve 13 through air passages 19 and 20, so that the air pressure applied to the interrupter i4 is the same as that applied to interrupter l7, and the air pressure applied to interrupter i2 is'the same as that applied to interrupter 15. Air is supplied under pressure from an extenal source through passage 2?. to the interrupters and the valve 18 exhausts to atmosphere through ducts 22.

The detailed view shown in FIG. 2 shows the construction of the circuit-breaker, which is symmetrical about the line XX. The description will rerer to that part of the circuit-breaker shown in the drawings and it will be understood that the part of the circuit-breaker to the other side of the line XX is of similar construction. The main circuit interrupters 12 and are mounted on a common central casing 23 by means of which they are connected together in series. The line connection ltl is connected to an end plate 24 on which is mounted a contact 25, the endplate being supported from the central casing 23 by 3,153,737 Patented Dec. 29, 1964 means of a porcelain insulator 26. The contact 25 is mounted for limited movement, but is usually referred to in the art as the fixed contact. Co-operating with the fixed contact 25 is a moving contact 27 which is arranged to slide within a cylinder 23 which forms part of the casing 23. The moving contact 27 is connected to a piston 29 by means of a rod 30. The rod co-operates with a lever 31 pivoted at 32 which engages a collar 33 to compress a spring 34 which is situated between the collar and a pivotally-niounted collar 35. The arrangement is such as to give a toggle action, the spring 34 urging the moving contact 27 to each of its extreme positions.

The passage 21 forms part of the base of the central casing 23, and communicates with a space 36 surrounding the co-operating contacts 25, 27. The space 37 within the cylinder 28 is not in communication with the space 36 when the contacts 2, 27 are closed, but communicates directly with the passage 2%, and thus with the exhaust valve 13. The passage 25 from the contacts 25, 27 to the exhaust valve 18 is of relatively large volume, conpared with the passage 19, and communicates, when the exhaust valve is open, with the ducts 22, which are formed in the casing 33 of the exhaust valve.

The valve 18 is of the balanced type and is loaded to the closed position by a spring 39 between an inwardlydirected flange 18A of the exhaust valve and a fixed abutment 38A forming part of the casing 33. The interior of casing 38 is connected through a conduit with the space 36, so that it is in communication with the pressure source. The valve is provided with an annular operating piston 41, the space below which can be placed in communication either with the pressure source, or with atmosphere, as will hereinafter be described, and the space above which has a restricted communication 41A to atmosphere.

Attached to the upper end of the casing 33 is a hollow ceramic insulator 42, the interior of which forms a chamber 43 which is in direct communication with the passage ];9. The end of the insulator 42 remote from the casing 38 is closed by an endplate 44 which is electrically connected to the resistor 13. Attached to the endplate is a cylindrical member defining a chamber n), which is completely enclosed except for a small opening 47 in the end wall 43 of the cylindrical member 45.

The end wall 43 forms one contact of the resistor circuit interrupter 14. Within chamber and coaxial with the cylindrical member 45 is a further cylinder 4% containing a plunger 5t one end of which forms the movable contact of the resistor circuit interrupter; the other end of the plunger St is formed with a piston 51. Compression springs 52 extend between the end of the cylinder and one face of the piston 51 and load the plunger to the right as seen in the figure. The other face of the piston 51 forms a wall of the chamber 53, this chamber communicating through a conduit 54 with the interior of casing 353, and thus with the compressed air supply. The interior of cylinder 49 to the left of the piston 51 as seen in the drawing communicates with the chamber 43 through a hole 56 which is positioned so that it cannot communicate with the chamber 53. The moving contact 59 can make contact with the end 48 of cylinder 45, which forms the fixed contact, when the springs 52 are sufiiciently compressed.

A groove 57 is cut in the end 43, communicating both with the bore of the hole 47 and withthe outside of the cylinder 45, i.e. with chamber 43, whether or not the contacts 43. 59 are touching one another.

The operating mechanism comprises a vertical rod which is biased upwardly by a spring so, as to move upward when the operating detent (not shown) is tripped. A lever till pivoted near its centre is connected at one end to the rod 58 and at its other end to the centre of a bellcrank lever .61, the ends of which are connected respectively to an operating rod 62 and to a rod 63 which is connected in turn to the end of lever 31 remote from the rod 39.

The operating rod 62 has adjacent each end a valve member; the valve members 64, 65 are loaded -respectively by springs 66;, 67 towards the operating rod. One valve member-6d is in communication through conduit .68 with the space 69 on the left of piston 29 as seen in the drawing; in one position (that toward which it is springloaded) the valve member 64 places the space 69 in communication through conduit 70 with the passage 21, and in the other position it places the space 69 in communication with atmosphere through port 71. The space 72 on the right of piston 29 is in communication through conduit "73 with the passage 20. The other valve member .65 is in communication through conduit 74 with the space 75 below the annular operating piston 41 of the exhaust valve 18, and in the position toward which it is spr-ing-loaded places the space 75 in communication with atmosphere through port 76; in its other position it places the space in communication with the passage 21 through conduit 77.

A modification of the end of cylinder .45 is shown in FIG. 3, in which the cylinder completely closes the space 46 except for the hole 47 in the end 48 of the cylinder which comprises one contact of the interrupter. A nonreturn valve 78 is fitted in the modified version communicating with the chamber 46 inside the cylinder 45, and with the chamber 43. The non-return valve is made so that gas may flow out from the chamber 46 when the hole 47 is blocked, but not inwardly.

The operation of the circuit-breaker will now be described. When the main interrupters 12 and'15 are closed, and the corresponding electric circuit is made, those parts of the interrupters 12, 14, 15 and 17 in communication with the exhaust valve 18 contain air under pressure. When the main electric circuit is to be broken the exhaust valve 18 is opened to atmosphere; air then moves from the interrupter 14 through passage 19 and from the main interrupter 12 through passage 20 towards the exhaust valve. This is effective in succession firstly to close the resistor circuit interrupters 14 and 17, thus bringing the resistors 13 and 16 into circuit in parallel with the main circuit interrupters 12 and 15, and then secondly to open the main circuit interrupters 12 and 15. The exhaust valve 18 is then closed, and this causes the resistor circuit interrupters 14 and 17 to open. These operations will be described in greater detail hereinafter.

The interrupters 14 and 17 operate simultaneously with each other and the interrupters 12 and 15 operate simultaneously with each other, and it will be understood that although the operation is described principally in relation to the interrupters 12 and '14, the interrupters 15 and 17 operate in the same manner.

The timing of the sequence of operation of these two pairs of interrupters is controlled by the design of the air passages 19 and 29, wherein the passage 1h is made effectively of smaller volume than the passage 2% so that air takes a shorter time to .depressurise the resistor circuit interrupters 1,4 and 17 than to depressurise the main circuit interrupters 12 and 15. This ensures the closing of the resistor circuit interrupters 14 and 17 before the main interrupters 12 and 15 open.

When the circuit-breaker is tripped, the rod 58 moves upwards rocking the lever 6,0. about its pivot and thus, through hell crank lever 61, moving the member 62 down. This moves the valve member 65 to place the space 75 beneath the operating piston of valve member 18 in communication with the passage 21 which contains air under pressure. The exhaust valve 15 thus opens, and air then flows from the chamber 46 through hole 47 and from within the cylinder 49- through hole 56 into space 43, and thence through the passage 19 and the exhaust valve 18 to atmosphere. The pressure of the air supplied through conduit 54 acting on the right-hand face of piston 51 overcomes the force of springs 52 and forces the contact 51) to the left to make abutment with the fixed contact 48, thus completing the resistor circuit. The chamber 46 continues to discharge through the grooves 57 until the pressure of the gas in the chamber 4-6 is equal to that of the gas in the chamber 4-3.

On opening of the exhaust valve 18 gas also flows from the space 72 on the right-hand side of piston 29 through passages 73, 26 and thence to atmosphere through the exhaust valve '16. Since the left-hand side of piston 29 is still subjected to the high pressure in passage 21 through conduits 66, 70, the piston 29 and moving contact 27 move to the right, breaking the circuit through the main contacts 25, 27. This takes place subsequent to the resistor circuit interrupter contacts 48, 56 having made.

In the alternative construction shown in FIG. 3, cham her 46 may discharge through the non-return valve 78.

It will be appreciated that a blast of air occurs between the main contacts as they separate, and this extinguishes the are; at the same time a flow of current is established through the resistor 13 and the resistor interrupter 14.

Opening of the main contacts 25, 27 also causes the operating rod 62 to be reset to its central position, through lever 31, rod 63, and lever 61, thus allowing valve to move upward under the influence of spring v67'. This position of the components, at the instant after the valve 65 has moved upward and before closing of the exhaust valve 18, is shown in FIG. 4. This causes the space '75 to be vented to atmosphere, and the exhaust valve 18 therefore closes again under the influence of spring 39.

On closing of the exhaust valve, the chamber 43 rapidly increases in pressure, being connected to the passage 21 through spaces 36, 37. Because the groove 57 is of small cross-section, gas only passes through it very slowly, and thus the pressure in the chamber (13 will be higher than that in chamber 46 within cylinder .45. Moreover, as the pressure in chamber 43 rapidly becomes equal to that in chamber 53, the springs 52 will cause the plunger 53 to move to the right, breaking the electrical contact and exposing the hole 4-7. Gas then passes with high velocity from chamber 43 through hole 47 into chamber 46, carry-- ing with it the products of the arc and thereby rapidly deionising the arc gap.

Closing of the exhaust valve 18 also causes the pressure in passage 20 and space 72 to rise until it is equal to that in chamber 36. The pressures on both sides of piston 29 are then equalised and the moving contact remains where it is, under the restraint of the toggle spring 34.

To close the main contacts 25, 27 the rod 58 is moved downward against the spring 59. This rocks lever 60 and raises the central pivot of bell crank 61, which in turn raises the operating rod 62. This actuates valve 64 to vent the space 69 on the left-hand side of piston 29 to atmosphere, through conduit 68 and port 71. As the space 72 is still connected to passage 21 through conduit 73, space 37 and space 36, the piston 29 is caused to move to the left, bringing contact 27 into abutment with the fixed contact 25.

The movement of piston 29, through lever 31, rod 63 and bell crank lever 61, causes the operating rod 62 to be reset to its central position, and valve 64 then moves downward under the influence of spring 66. This places space 69 in communication with the pressure source, thus equalising the pressures on each side of piston 2); the movable contact 27 remains in the closed position under the influence of the toggle spring 34.

What we claim as our invention and desire to secure by Letters Patent is:

1. A gas-blast electric circuit-breaker having a main circuit interrupter, a resistor connected electrically in parallel with said main circuit interrupter, a resistor circuit interrupter connected in series with said resistor, closed chamber means enclosing said main and resistor circuit interrupters, a source of gas under pressure connected to said closed chamber means, first pressurearesponsive a means connected to said main circuit interrupter to operate it, second pressure-responsive means connected to said resistor circuit interrupter to operate it, an exhaust valve operable independently of said interrupters, first passage means connecting said first pressure-responsive means to said exhaust valve, second passage means connecting said second pressure-responsive means to said exhaust valve, whereby opening of said exhaust valve causes operation of both said main circuit interrupter and said resistor circuit interrupter, and further passage means connecting said closed chamber means on the side of said main circuit interrupter remote from said pressure source with said exhaust valve, whereby on opening of said main circuit interrupter a blast of said gas under pressure passes over said main interrupter and through said exhaust valve.

2. A gas-blast electric circuit-breaker comprising a main circuit interrupter, a resistor connected electrically in parallel with said main circuit interrupter, a resistor circuit interrupter connected in series with said resistor, a source of gas under pressure connected to said main circuit interrupter, first pressure-responsive means connected to said main circuit interrupter, means defining a first chamber having said first pressure-responsive means as one of its walls and so arranged that a reduction of pressure in said chamber causes said first pressure-responsive means to move in the sense to open said main circuit interrupter, second pressure-responsive means connected to said resistor circuit interrupter, means defining a second chamber having said second pressure-responsive means as one of its walls and so arranged that a reduction of pressure in said chamber causes said second pressure-responsive means to move in the sense to close said resistor circuit interrupter, an exhaust valve operable independently of said interrupters, first passage means connecting said first chamber with said exhaust valve, second passage means connecting said second chamber with said exhaust valve, whereby on opening of said exhaust Valve there is a reduction of pressure in said first and second chambers whereby the main circuit interrupter is closed and the resistor circuit interrupter is opened, and further passage means connecting said main circuit interrupter to said exhaust valve, whereby on opening of said main circuit interrupter a blast of said gas under pressure passes over said main interrupter and through said exhaust valve.

3. An electric circuit-breaker as claimed in claim 2 wherein the etfective volume of said second passage means is less than the effective volume of said first passage means, whereby said second pressure-responsive means is caused to move to close said resistor circuit interrupter before said first pressure-responsive means is caused to move to open said main circuit interrupter.

4. An electric circuit-breaker as claimed in claim 2 comprising also resilient means acting on said second pressure-responsive means to load said resistor circuit interrupter in the sense of opening, means defining a third chamber on the side of said second pressure-responsive means remote from said second chamber, and means for supplying fluid under pressure to said third chamber, whereby on closing of said exhaust valve the increase in pressure in said second chamber together with the load imposed by said resilient means overcomes the pressure in said third chamber and causes said second pressureresponsive means to move in the sense to open the resistor circuit interrupter.

5. A gas-blast electric circuit-breaker having two main circuit interrupters connected in series, two resistors connected electrically in series with one another and in parallel with said main circuit interrupters, two resistor circuit interrupters connected in series with said resistors, closed chamber means enclosing said main and resistor circuit interrupters, a source of gas under pressure connected to said closed chamber means, first pressure-responsive means connected to each of said main circuit interrupters to operate them, second pressure-responsive means connected to each of said resistor circuit interrupters to operate them, an exhaust valve operable independently of said interrupters, first passage means connecting said first pressure-responsive means to said exhaust valve, second passage means connecting said second pressureresponsive means to said exhaust valve, whereby opening of said exhaust valve causes operation both of said two main circuit intcrrupters and of said two resistor circuit interrupters, and further passage means connecting said closed chamber means on the side of each of said two main circuit interrupters remote from said pressure source to said exhaust valve whereby on opening of said main circuit interrupters a blast of said gas under pressure passes over said main interrupters and through said exhaust valve.

6. A gas-blast electric circuit-breaker comprising an insulator defining a first chamber, a source of gas under pressure connected to said chamber, an exhaust valve connected to said chamber, a movable contact mounted for movement within said chamber and operable by the sup ply of gas under pressure to said chamber and by the exhausting of gas under pressure from said chamber, said movable contact forming one contact of the circuitbreaker, means within said first chamber defining a second chamber which is completely enclosed except for an opening at one end, said end comprising another contact of the circuit-breaker and co-operating with said one contact, and said opening being of such a size that when gas under pressure is supplied from said source to within said first chamber to cause opening of said circuit-breaker, said gas passes with high velocity through the opening and into the second chamber carrying with it products of any are formed thereby deionizing the arc gap.

7. An electric circuit-breaker as claimed in claim 6 wherein one or more grooves are cut in that end of the second chamber which incorporates said opening, the grooves communicating both with the interior of the opening and with the outside of the second chamber so that whether or not the circuit-breaker contacts are in the closed position the pressure of the gas in the second chamber becomes equal to the pressure of the gas in the first chamber.

8. An electric circuit-breaker as claimed in claim 6 comprising a non-return valve fitted to the second chamber to allow gas to escape from said second chamber so that Whether or not the circuit-breaker contacts are in the closed position the pressure of the gas in the second chamber becomes equal to the pressure of the gas in the first chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,255,225 Radley Feb. 5, 1918 2,665,351 Forwald Ian. 5, 1954 2,955,182 Caswell et al. Oct. 4, 1960 FOREIGN PATENTS 760,355 Great Britain Oct. 31, 1956 

1. A GAS-BLAST ELECTRIC CIRCUIT-BREAKER HAVING A MAIN CIRCUIT INTERRUPTER, A RESISTOR CONNECTED ELECTRICALLY IN PARALLEL WITH SAID MAIN CIRCUIT INTERRUPTER, A RESISTOR CIRCUIT INTERRUPTER CONNECTED IN SERIES WITH SAID RESISTOR, CLOSED CHAMBER MEANS ENCLOSING SAID MAIN AND RESISTOR CIRCUIT INTERRUPTERS, A SOURCE OF GAS UNDER PRESSURE CONNECTED TO SAID CLOSED CHAMBER MEANS, FIRST PRESSURE-RESPONSIVE MEANS CONNECTED TO SAID MAIN CIRCUIT INTERRUPTER TO OPERATE IT, SECOND PRESSURE-RESPONSIVE MEANS CONNECTED TO SAID RESISTOR CIRCUIT INTERRUPTER TO OPERATE IT, AN EXHAUST VALVE OPERABLE INDEPENDENTLY OF SAID INTERROPTERS, FIRST PASSAGE MEANS CONNECTING SAID FIRST PRESSURE-RESPONSIVE MEANS TO SAID EXHAUST VALVE, SECOND PASSAGE MEANS CONNECTING SAID SECOND PRESSURE-RESPONSIVE MEANS TO SAID EXHAUST VALVE, WHEREBY OPENING OF SAID EXHAUST VALVE CAUSES OPERATION OF BOTH SAID MAIN CIRCUIT INTERRUPTER AND SAID RESISTOR CIRCUIT INTERRUPTER, AND FURTHER PASSAGE MEANS CONNECTING SAID CLOSED CHAMBER MEANS ON THE SIDE OF SAID MAIN CIRCUIT INTERRUPTER REMOTE FROM SAID PRESSURE SOURCE WITH SAID EXHAUST VALVE, WHEREBY ON OPENING OF SAID MAIN CIRCUIT INTERRUPTER A BLAST OF SAID GAS UNDER PRESSURE PASSES OVER SAID MAIN INTERRUPTER AND THROUGH SAID EXHAUST VALVE. 